In general, in order to move a platform such as those used in high precision equipment, such as a stage used in a handler or a tester for Automatic Test Equipment (ATE), multiple actuators or linear motors are required in order to achieve multiple degrees of freedom. For example, the device disclosed in U.S. Pat. No. 5,334,892, the disclosure of which is incorporated herein by reference, relies upon an a first linear motor to move in an X and a second linear motor to move in a Y direction. In addition, in U.S. Pat. Nos. 5,982,053 and 6,215,206, the disclosures of which are incorporated herein by reference, an actuator for use with a stage is able to both rotate about a theta axis and to move along a Z axis that is parallel with the theta axis. As such, using these conventional devices, in order to move in the X direction, the Y direction, and to rotate about a theta axis, three actuators would be required.
U.S. Pat. No. 4,327,596, which is incorporated herein by reference, discloses a single motor that engages a pulley system that selectively moves a platform in an X and Y direction. However, this system lacks a rotational ability. Further, the solution proposed in U.S. Pat. No. 4,327,596 has a complex construction and would take up an unacceptable amount of space for use in certain high precision equipment, such as Automatic Testing Equipment. Lastly, this solution does not have a positive drive, which would allow for errors and slippage and/or the string tension which is not be acceptable in high precision equipment.
It is an object of the invention to provide a single motor, multi axis stage positioning system having the ability to move in X and Y directions.
It is an additional object of the invention to provide a single motor, multi axis stage positioning system having the ability to move in X and Y directions as well as rotating about a theta axis.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other objects of the invention, an embodiment of an actuator system for moving a platform includes a motor which rotates a rotational element, a transmission system which engages the motor and selectively engages the platform, a first lock which engages the transmission system such that the transmission system moves the platform according to a rotation of the rotational element, and a second lock which engages the transmission system such that the transmission system moves the platform moves according to the rotation of the rotational element, where, when the first lock engages the transmission system and the second lock does not engage the transmission system, the transmission system moves the platform in a first direction according to the rotation of the rotational element, and when the first lock does not engage the transmission system and the second lock engages the transmission system, the transmission system moves the platform in a second direction other than the first direction according to the rotation of the rotational element.
According to an aspect of the invention, the actuator further includes a rotation lock that selectively engages the transmission system such that, when the rotation lock is locked, the platform rotates about a third direction according to the rotation of the rotational element.
According to another aspect of the invention, the transmission system further comprises first and second rails and first and second connectors, the first rail is connected to the rotational element so as to move in the first direction according to the rotation of the rotational element, the second rail is connected to the rotational element so as to move in the second direction according to the rotation of the rotational element, when the first lock engages the transmission system, the first lock connects the first connector with the first rail and the platform and the platform moves with the first rail according to the rotation of the rotational element, and when the second lock engages the transmission system, the second lock connects the second connector with the second rail and the platform and the platform moves with the first rail according to the rotation of the rotational element.
According to a further aspect of the invention, the actuator further includes a first guide unit which is slideably connected to the first rail so as to guide the movement of the first rail in the first direction and to prevent a movement of the first rail in the second direction, and a second guide unit which is slideably connected to the second rail so as to guide the movement of the second rail in the second direction and to prevent a movement of the second rail in the first direction.
According to another embodiment of the invention, a movable stage system includes a platform, a motor which rotates a rotational element, a transmission system engaged with the motor and selectively engaged with the platform, a first lock which engages the transmission system such that the transmission system moves the platform according to a rotation of the rotational element, a second lock which engages the transmission system such that the transmission system moves the platform moves according to the rotation of the rotational element, and a controller which controls the motor and first and second locks such that, when the first lock engages the transmission system and the second lock does not engage the transmission system, the transmission system moves the platform in a first direction according to the rotation of the rotational element, and when the first lock does not engage the transmission system and the second lock engages the transmission system, the transmission system moves the platform in a second direction other than the first direction according to the rotation of the rotational element.